1. Field of the Invention
The present invention relates to a power supply section of an electronic apparatus or a camera, and more particularly to a cell change technique in an electronic apparatus or a camera which is driven by a fuel cell.
2. Description of the Related Art
In recent years, development of utilizing a fuel cell as a compact power supply source in a portable apparatus or the like has been pursued. A fuel cell utilizes an electric current which is generated when hydrogen (H2) contained in fuel reacts with oxygen (O2) to form by-product water (H2O). Therefore, by supplying fuel such as a hydrogen gas, methanol or the like, into a fuel cell, electrical current created from the ionic exchange between the H2 and the O2, may be used as a source of electricity to power various apparatuses and devices.
The fuel cell has an energy density higher than that of a conventional battery (primary battery, secondary battery). Therefore, if the fuel cell is used as a power supply source for a compact electronic apparatus, long-duration drive, compactness and light weight of the compact electronic apparatus can be attained. In particular, a camera, which has been multi-functionally developed, can also support the increase of power consumption. Further, since the fuel cell may be refilled with fuel, electric power can successively be generated. Accordingly, the inconvenience of frequent change and recharging of a battery as in a conventional battery is eliminated, and the convenience, when the camera is used, is remarkably improved.
For instance, a portable electric apparatus has been proposed which includes a power generation unit, a fuel unit for supplying hydrogen gas to the power generation unit, a joint section which is mounted on a hydrogen supply path between the fuel unit and the power generation unit and which detachably connects the fuel unit and the power generation unit, a mini-valve for opening and closing the supply of hydrogen gas, and a pressure regulator for regulating pressure of hydrogen gas (for example, see Japanese Patent Application Laid-Open No. 10-64567 (corresponding to U.S. Pat. No. 5,976,725)).
Further, a technique which is configured to allow a fuel cell for mounting on apparatuses to be contained in a portable apparatus has been disclosed (for example, see Japanese Patent Application Laid-Open No. 9-213359 (corresponding to U.S. Pat. No. 6,057,051)).
However, a fuel cell configuration in the above-described conventional examples does have disadvantages. That is, with respect to the fuel cell configurations disclosed in Japanese Patent Application Laid-Open Nos. 10-64567 and 9-213359, the capacity of fuel and a voltage to be outputted are uniquely predetermined as long as a fuel cell which is designed to be used for an associated apparatus is used. Thus, users can not freely choose these values in accordance with apparatus use. For example, when a camera is driven by a fuel cell, even if it is intended to carry out photographing at an increased speed in a continuous-shooting mode higher than that in a normal condition, it is difficult to increase a voltage for driving a motor if only a predetermined specific fuel cell having set performance characteristics is used. Thus, the camera is not capable of supporting the attempt at increased speed continuous-shooting. Also, likewise, when it is intended to continuously use a camera for a time as long as possible, if a fuel cell having a large capacity of fuel is used, time of use can be made longer. However, if only a predetermined specific fuel cell having specific design parameters can be used, it becomes impracticable to use a fuel cell having different design parameters.
As a result, due to limitations inherent with currently available fuel cell technologies for small electronic devices, it is difficult to flexibly meet various performance characteristics that users require for such apparatuses.